feat: add official Codex skill and harden task execution

Install and update artemis-use with task diagnostics and plugin guidance. Preserve cross-device file receipts, review canonical reports, guard stage transitions and reduce small history summaries. Improve exploration lifecycle, request recovery and browser live connections.

scripts/start.ps1

@@ -306,13 +306,13 @@ if (-not (Test-Path -LiteralPath (Join-Path $RootDir '.env'))) {
     }
 }
 if (-not $SkipMcpSync) {
-    Write-Host (Get-LaunchText '   [CHECK] Installing/updating Codex MCP...' '   [检查] 正在安装或更新 Codex MCP...') -ForegroundColor Cyan
+    Write-Host (Get-LaunchText '   [CHECK] Installing/updating Codex MCP and artemis-use Skill...' '   [检查] 正在安装或更新 Codex MCP 和 artemis-use Skill...') -ForegroundColor Cyan
     & $ArtemisPython (Join-Path $ScriptDir 'update_installation.py') mcp
     if ($LASTEXITCODE -ne 0) {
-        Write-Host (Get-LaunchText '   [ERROR] Codex MCP synchronization failed. Fix the configuration above, or use -SkipMcpSync to run the web UI without MCP.' '   [错误] Codex MCP 同步失败。请修复上方配置；仅需启动网页时可使用 -SkipMcpSync。') -ForegroundColor Red
-        exit 1
+        Write-Host (Get-LaunchText '   [WARN] Codex integration sync failed; existing configuration is preserved. Continuing web startup.' '   [提示] Codex 集成同步失败；保留原配置，继续启动网页。') -ForegroundColor Red
     }
 } else {
+    $env:ARTEMIS_SKIP_CODEX_SYNC = '1'
     Write-Host (Get-LaunchText '   [SKIP] MCP synchronization was skipped.' '   [跳过] 已跳过 MCP 同步。') -ForegroundColor Yellow
 }
 if ($SetupOnly -and -not $PrepareOnly) {